This invention relates to lumber processing and more particularly to a transfer mechanism which transfers boards from a conveyor conveying boards in adjacent relationship onto a conveyor that receives and conveys the boards in a desired fixed relationship.
Lumber processing is highly automated and in certain processing stations, the boards need to be precisely spaced apart when entering the station. To achieve this spaced relationship, the boards are commonly transferred from a conveyor where the boards are in close or abutting relationship, e.g., as when coming from an unscrambler, onto a second conveyor having lugs that determine the desired spacing. A transfer mechanism controls the transfer from one conveyor onto the other to assure the relationship desired. This invention is directed to such transfer mechanism.
A typical transfer mechanism employs an intermediate pick off wheel and a stop member. The board movement is stopped on the first conveyor (although the conveyor typically continues to slide under the boards) and each leading board in turn is picked off the first conveyor by the pick off wheel and.carried over onto the next conveyor in timed sequence.
The mechanism of such prior transfer mechanisms is complex, slower than desired, subject to misfeeding of the boards and expensive. The present invention is directed to greater speed, greater accuracy, is simpler in design and less expensive.
In a first preferred embodiment, the first conveyor is provided with a descending discharge end that is closely adjacent to and elevated over the receiving end of a second conveyor. A downwardly angled fixed slide member fills the gap between the conveyors and directs the boards off the discharge end of the first conveyor and toward the receiving end of the second conveyor. A fixed stop is provided on the slide and interrupts the movement of the board. The stop is positioned just above the end sprocket of the second conveyor. A camming wheel or member mounted to the shaft of the end sprocket of the receiving conveyor rotates with the end sprocket. Camming lobes on the wheel are strategically positioned to rise up under a leading board edge abutted against the stop and raises that board edge over the stop. The downward urging of the following boards pushes the board over the stop and onto the second conveyor. The lobes of the camming wheel or member are arranged on the wheel relative to the lugs on the second conveyor so that the boards are deposited on the second conveyor between the lugs.
A secondary stop in the form of a pivotal arm is provided to selectively stop the advancement of the boards prior to the fixed stop and nullifies the cam feeding of the boards. This allows the second conveyor to operate, e.g., to empty the second conveyor. The boards descending down the path of the first conveyor end and the slide are preferably biasingly urged to lay flat on the conveyor and slide until engaged by the lobes of the camming wheel or member.
A further embodiment believed to be an improvement over the above first preferred embodiment dispenses with the slide member. The further embodiment retains the descending discharge end of the first conveyor and effectively overlaps the two conveyors to enable the direct transfer of the boards onto the second conveyor from the first conveyor. A stop member stops the conveyance of the boards just prior to the overlap position and a camming wheel, similar to that of the first preferred embodiment, sequentially lifts the leading edge of the leading board over the stop for deposit onto the second conveyor.
These and other features and benefits of the invention will be more fully appreciated upon reference to the following detailed description and the drawings referred to therein.